


Si Fueris Romae

by wickedthoughts



Category: Supernatural
Genre: Anal Sex, Barebacking, Begging, Blood Drinking, Bloodplay, Bottom Sam, Bruises, Coming Untouched, Consensual, Demon Dean Winchester, Dom/sub, Established Dean Winchester/Sam Winchester, First Blade, Hair-pulling, Knifeplay, M/M, Mark of Cain, Orgasm Control, Plot What Plot/Porn Without Plot, Rough Sex, Season/Series 10 Spoilers, Sibling Incest, Top Dean
Language: English
Status: Completed
Published: 2015-02-06
Updated: 2015-02-06
Packaged: 2018-03-10 19:16:47
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,677
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3300626
Author URL: https://archiveofourown.org/users/wickedthoughts/pseuds/wickedthoughts
Summary: <blockquote class="userstuff">
              <p>Si fueris Romae, Romano vivito more; si fueris alibi, vivito sicut ibi. </p><p>(Or, if the demon is the only way Sam can have Dean, so be it.)</p>
            </blockquote>





	Si Fueris Romae

**Author's Note:**

> For an spnkink-meme prompt ([x](http://spnkink-meme.livejournal.com/92374.html?thread=36411862#t36411862))

* * *

"Roll over, Sammy."

He wakes to hear his brother hissing in his ear. Sam's not sure what time it is, how long he's been sleeping. He and Dean are in the same position they fell asleep in, naked, with his demon brother curled possessively around his taller frame. He can feel Dean's hard cock pressing insistently into the crack of his ass. Dean humps against Sam, warm skin rubbing together, a growl of pleasure from the demon resounding in his ear.

"Roll over."

Dean's tone shifts, hardens insistently like his cock. Sam knows better than to keep his brother waiting. He rolls onto his stomach.

"Good boy."

The demon purrs as he climbs on top of Sam's prone form. He lies flat against Sam, covering him, sliding his cock up and down along Sam's ass. Sam shivers. He shouldn’t like this, he really shouldn’t, but god help him he loves it. He’s loved it for so long, even before his brother became a demon. It doesn't make sense, but when Dean's on top of him like this it doesn't have to make sense. He needs this, needs Dean. Sam loves his brother, even this twisted version that he couldn't cure, and if this demon is the only way he can have Dean, so be it.

Dean pushes up on his arms and sits back on his haunches on the bed behind him. Sam doesn't need him to give the order before he's scrambling to his hands and knees, eyes forward, presenting his ass for Dean's use.

"Good boy."

Dean's hands bury themselves in Sam's long hair and yank backward, exposing his throat. Sam gasps with surprised pain.

"Had a good dream, Sammy," Dean tells him, stroking Sam's straining neck. "Made me horny. Need you to help me with that."

Dean's fingers trace his Adam's apple and Sam swallows hard.

"Yeah? What- what do you need?"

"Need my cock buried in your pretty ass, baby brother. Need to feel how tight and warm you are inside for me. Need you to beg for me."

"Okay," Sam gulps again as his cock begins to fill with blood. "Okay."

"Just okay?"

Sam's mouth twists into the facsimile of a grin. Desperate wide eyes and bared teeth.

"Better than okay, Dean. Perfect. Fuckin’ perfect."

He hears Dean sigh. A deep rumble of pleasure. He keeps a hold of Sam’s hair, but removes his hand from Sam’s throat. Sam hears the slide of Dean's rough hand on his hard cock, too impatient to wait long for his gratification.

"Beg for me, Sammy."

Dean shifts abruptly and retrieves his donkey-bone Blade from underneath his pillow, the place it always rests when Dean rests. The third partner in their relationship. Sam feels the jagged teeth of the Blade against his bared throat, sure to draw blood if he moves at all. He keeps his breaths measured as he obeys.

“Oh god, fuck me Dean. Please fuck me. I need you inside me so bad, please!”

Dean moans softly and releases Sam’s hair. Sam tenses his neck, but can’t prevent the prick of teeth against the skin of his throat. He feels tiny beads of blood well up and trickle down to his collarbone. He hears Dean fumbling one-handed for the lube he keeps on the bedside table.

“Please, Dean, oh please.”

He injects urgency into his plea and Dean’s responding groan sends more blood surging into his achingly hard cock. His act is over; he’s begging for real now. He needs this so fucking badly.

“Please!”

Sam keeps his eyes forward, focused intently on the headboard just the way Dean likes it, hears the wet slap of skin-on-skin as Dean slicks himself up, and then he feels Dean’s cock probing his entrance while Dean’s free hand squeezes the supple flesh of Sam’s ass, covering it with the remnants of the lube. All of Sam’s senses are on fire. He can see every grain of wood in the old headboard. He can feel the lube, cool and moist against his hole, and the Blade sharp against his throat. He smells his blood, his own sweat, but over all he smells Dean’s musk permeating the air. His brother is so powerful, always was even without the Mark and the black eyes, and Sam can feel that power about to consume him and he loves it so much. Loves it enough to give up his own power, once held so dearly, and surrender himself completely to the glorious monster Dean has become.

Dean’s cock finds his entrance, the head pushing its way slowly inside until with one quick, brutal thrust Dean buries himself balls-deep in Sam. They both groan with the feeling, the big brother pausing briefly to enjoy the grip on his cock as his little brother contracts around him. Then he’s fucking brutally, pounding himself into Sam with deep, wordless groans that Sam returns as he feels the rich fullness of Dean inside him. Dean’s always been skilled with his cock, no matter which orifice he’s using it on, and he finds Sam’s sweet spot almost immediately, sending spikes of pleasure shooting up Sam’s spine. His balls throb and swell as they draw up tight. His cock bobs, smacking against his flat stomach with the combined surge of blood and the violence with which Dean is taking him. His arms spasm and he locks them to prevent himself from slitting his own throat. He desperately wants to maneuver himself away from the Blade and take himself in hand, but he’s not allowed to touch his cock. That was one of the demon’s first rules, one that Sam agreed to only because of his memories of human Dean’s proficiency at making his little brother come with just his cock in his ass. He’s not been disappointed. The demon can often be crueler than the man ever was, but in the bedroom Sam can still pretend that nothing’s changed and that Dean remains himself.

“You stopped beggin’, Sammy.”

The hand holding the Blade tightens and Sam feels the sharp cut of teeth. Thicker trails of warm blood flow down his chest.

“I-I’m sorry. Oh god, fuck me harder! Please, please, harder. Please let me come, Dean, please!”

“Yeah,” Dean’s gruff speech slurs. “Don’t worry baby brother. I’m gonna take real good care of you.”

“Please-” Sam almost sobs. “Harder- please let me come- harder- rip me in half- tear me apart, Dean!”

Dean’s hand releases the flesh of Sam’s ass and moves to Sam’s neck, picking up the sticky redness there. Dean removes his hand and Sam hears him sucking the blood from his fingers, can imagine those gorgeous lips wrapped around Dean’s fingers as he take sustenance from Sam’s vitality. He can fully appreciate the irony here. That once Sam was human drinking demon’s blood, and now Dean is a demon drinking Sam’s human blood. He’d be lying if he said he hasn’t thought about asking Dean to let him drink from him. Embrace the darkness inside himself to better understand the darkness that’s been unleashed inside Dean now. That would be the final step though, the point of no return for the brothers Winchester, and Sam’s not sure if he’s truly ready for that yet. Not yet. Someday, maybe.

“You taste so good, Sam. So fuckin’ good.”

The hand returns to Sam, higher up on his jutting hipbone, grabbing hard enough that Sam knows there will be a mottled purple-blue bruise when this is over. He moans, thrusting his hips backward to help Dean pound into that spot that’s sending thrills of ecstasy through him. Dean drops the Blade to the pillow and brings the hand to Sam’s other flank, symmetrically gripping and bruising when he plows Sam’s orgasm out of him.

Sam’s hair falls in his face, wet with his exertion, as his head jerks back and forth. He grunts and groans, arms spasming once more as he holds himself up. His balls throb and his cock pulses his thick essence onto the bed. He pants with pleasure.

“What do we say, Sammy?”

“Th-thank you. Thank you.”

“So polite,” Dean sounds smug while his thrusts become short and stuttering, signalling the fast approach of his own climax. “Such a good boy, Sammy.”

Sam’s nickname becomes longer and higher at the end when Dean comes. Sam clenches himself around his brother to make it as good as possible. Dean’s fingers grasp his hips so tightly that Sam’s certain he’s broken the skin. The warm rush of Dean’s orgasm fills him, and Sam closes his eyes, receiving it gladly.

“Down, boy,” Dean commands when he’s finally sated. Sam obliges, collapsing on the bed, his firm belly soaking in the wet stain of his own release and his cheek pressed against the dull bone of the First Blade. The motion unsheathes Dean’s softening cock. A moment later the older Winchester collapses as well. He breathes heavily in Sam’s ear, covering the younger man with his body.

“So good, Sammy. So fucking good.”

“Thank you.”

“Yeah,” Dean’s already drifting back to sleep. “You’re welcome.”

Dean’s breathing becomes soft and measured. He nuzzles into Sam’s neck, unconsciously tender in his slumber. Sam closes his eyes and relishes the affection. He still misses the old Dean, but he’s found that he’s coming around to the new version. No inhibitions, no guilt, more violence, but essentially his brother, complete with his devotion to Sam. And isn’t that all Sam really needs from Dean?

Sam can feel the steady beat of Dean’s heart against his back. He imagines the organ, robust with demonhood, pumping Dean’s blood. He imagines the red liquid flowing from a severed vein in wrist or neck or thigh. He imagines the way Dean will taste on his tongue as he savors Dean’s blood, better somehow than any of the other demons he’d had all those years ago. The still small voice of his conscience protests, but the stronger voice of his id drowns it out. He could do it now. He could, but-

_Not yet._

Sam falls asleep.


End file.
